#1010653 - 06/19/19 11:02 AM
Low holing by salmon ranchers
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Returning Adult
Registered: 11/17/04
Posts: 353
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"Productivity and life history of sockeye salmon in relation to competition with pink and sockeye salmon in the North Pacific Ocean" Canadian Journal of Fisheries and Aquatic Sciences, Volume 72, Number 6, June 2015.
I don't know if this paper has been discussed before so I apologize if it has. In brief it points out that sockeye salmon returns to rivers from Alaska to Washington have almost all declined over the past 50 years and in particular since the 1970's. It tests the hypothesis that much of this decline is due to competition with pink salmon for food in the open ocean (one mechanism that can operate on such a large geographical scale). There is strong support for this hypothesis. So, as Alaska, Russia and others dump more pink salmon (and chum salmon) into the ocean, the shift the returns to increases in their local waters at the expense of other areas (WA, BC).
Here's the key points - quoted from the discussion: "The productivity of sockeye salmon populations in BC, Southeast Alaska, and Washington has declined similarly over time and intensified in recent years, suggesting that the primary causal mechanism driving this decline operates at a large, multiregional spatial scale at sea (Peterman and Dorner 2012). We examined the productivity and life history characteristics of up to 36 sockeye populations — including 18 Fraser River populations — spanning this region of similar trends in productivity over the past 55 years to test whether competition between pink and sockeye salmon for resources at sea may have contributed to these declines. We found consistent evidence that productivity of these sockeye salmon populations has declined in response to increasing abundance of pink salmon in the North Pacific Ocean. Furthermore, length-at-age of male and female Fraser River sockeye salmon was inversely correlated with both pink and sockeye salmon abundance, and age-at-maturity of Fraser River sockeye salmon was positively correlated with pink salmon abundance. These findings were consistent for both detrended and raw datasets involving North Pacific pink salmon, indicating that the influence of pink salmon was detected across both short and long time scales. The abundance of pink salmon in the North Pacific alternates from high (odd-numbered years) to relatively low abundance (even-numbered years), and this alternating-year pattern was also observed in sockeye salmon productivity, length-at-age, and age at maturity. Thus, the evidence for competition between pink and sockeye salmon comes from both hierarchical modeling of patterns over time and the natural experiment provided by the 2-year life cycle of pink salmon and its alternating-year abundance. Our analyses predict that an increase in pink salmon abundance from 150 million to 600 million fish (i.e., the observed range) would lead to a ~67% reduction in total abundance of returning Fraser River sockeye salmon (catch and spawning escapement combined) after controlling for other variables in the model such as parental spawning abundance."
Note that since about 1980, Alaska's hatchery plants have gone from ~100million to about 1.6 billion and that most of those plants are chum and pink.
Edited by SeaDNA (06/19/19 11:04 AM)
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#1010654 - 06/19/19 11:07 AM
Re: Low holing by salmon ranchers
[Re: SeaDNA]
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River Nutrients
Registered: 11/21/07
Posts: 7437
Loc: Olema,California,Planet Earth
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The growth in pink populations, particularly the AK releases, have been correlated with Chinook declines, SRKW declines, seabird declines, coho declines, and declines in size at age in Chinook and coho.
What I want to know is are the really too many pinks (maybe there are) or too few of their food resources because those are harvested too?
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#1010716 - 06/20/19 09:17 AM
Re: Low holing by salmon ranchers
[Re: SeaDNA]
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Returning Adult
Registered: 11/06/05
Posts: 401
Loc: Western Washington
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Similar hypotheses have been published with regard to hatchery chum salmon production in and around Japan... and how this production competes with the various large groups of North American salmon also growing to maturity in the North Pacific... Alaska hatchery pink salmon production being one.
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#1010725 - 06/20/19 12:09 PM
Re: Low holing by salmon ranchers
[Re: SeaDNA]
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River Nutrients
Registered: 11/21/07
Posts: 7437
Loc: Olema,California,Planet Earth
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Both pink and chum feed on smaller items, including probably younger ages, than the other salmon species. They also get out to sea ahead of sockeye so they can clean up there, too.
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#1010863 - 06/22/19 08:48 AM
Re: Low holing by salmon ranchers
[Re: SeaDNA]
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Repeat Spawner
Registered: 12/06/07
Posts: 1388
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Why would produce those huge numbers of Pink and Chum? Other than the eggs, their is hardly any commercial value in them?
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"Life moves pretty fast. If you don't stop and look around once in a while, you could miss it.” – Ferris Bueller. Don't let the old man in!
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#1010878 - 06/22/19 01:57 PM
Re: Low holing by salmon ranchers
[Re: SeaDNA]
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River Nutrients
Registered: 11/21/07
Posts: 7437
Loc: Olema,California,Planet Earth
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Don't know who they sell them to but the hatcheries are run by the private-non-profits who tax the fishermen (primarily seiners) to run th program. Makes enough in taxes to run the program and the fishermen support it so there must be a market.
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#1010879 - 06/22/19 02:22 PM
Re: Low holing by salmon ranchers
[Re: SeaDNA]
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River Nutrients
Registered: 08/26/02
Posts: 4709
Loc: Sequim
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#1010942 - 06/24/19 10:53 AM
Re: Low holing by salmon ranchers
[Re: bushbear]
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River Nutrients
Registered: 10/22/09
Posts: 3020
Loc: University Place and Whidbey I...
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Pinks...it's all about the volume and how nicely they go into a can leading to a good price point.
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#1011000 - 06/25/19 10:43 PM
Re: Low holing by salmon ranchers
[Re: RUNnGUN]
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Returning Adult
Registered: 11/17/04
Posts: 353
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Why would produce those huge numbers of Pink and Chum? Other than the eggs, their is hardly any commercial value in them? See this link. Soon after hatching, pink and chum salmon fry can be transferred directly from fresh water incubators to salt water net pens, where they acclimate and are fed for a few months and released. King, sockeye, and coho salmon, on the other hand, must spend a year or more rearing in fresh water before developing to the smolt stage, when they can tolerate salt water. Pink salmon will return two years after eggs are collected. Other species have longer production cycles. Thus, it comes down to water, expense, and value of the return. These are the economic factors that PNP Hatchery Board of Directors and their constituents weigh in operating their hatcheries. Although king, sockeye, and coho salmon garner higher prices per pound at harvest, chum and pink salmon cost less to rear and generally provide a higher economic return on production costs, requiring less "cost recovery" harvest to pay for hatchery operations and leaving more fish for the commercial and sport fisheries to harvest.
As a result, most of Alaska’s PNP hatchery production is pink and chum salmon..
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#1011007 - 06/26/19 07:18 AM
Re: Low holing by salmon ranchers
[Re: SeaDNA]
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River Nutrients
Registered: 11/21/07
Posts: 7437
Loc: Olema,California,Planet Earth
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Plus, if you produce Chinook and coho in those PNPs you have to share them with the (in the AK situation) non-paying recs.
Back immediately post-Boldt the Leg had WDF build a number of chum hatcheries and significantly expand chum production for the commercials who were hammered by the decision. The economics of pink, chum, and sockeye (when IHNV can be handled) are so good as they require so little water, food, or infrastructure. A trap, incubation, and release means. Maybe a small raceway or two to feed for a few days.
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